Surface of human hard dental tissues (enamel and dentine) was treated using a helium single-electrode atmospheric pressure plasma jet (APPJ) with the aim of enhancing surface properties of treated material. Modification of the enamel and dentine surface was observed using contact angle measurements and X-ray photoelectron spectroscopy. Even a short treatment time (ae1 s) lead to a significant reduction in the contact angle: 45% for the dentine and 32% for the enamel. After the treatment, the water contact angle tends to return to original (untreated) value and it is shown that stability of wetting strongly depends on the duration of treatment. The surface of the untreated teeth samples consisted mostly of the elements C, O, N, Ca and P. Their relative concentrations changed during 9-min He APPJ treatment. Significant decrease of C and N relative concentrations suggested the removal of adsorbed carbon and nitrogen species and disclosure of underlying inorganic hydroxyapatite structure. The Ca/P ratio has increased from 1.26 to 1.72, which is very close to an ideal ratio for the highest volume of remineralisation of the human dental enamel. Oxidation of the transparent organic matrix in the enamel, one of the major processes in tooth bleaching, was confirmed with the increase of O concentration, from about 31 to 46 at.%. Helium APPJ treatment therefore proved to be a potential tool for chemical surface modification of hard human dental tissues.